In the music industry, it has often been desirable to alter the sound produced from a musical instrument using sound effects. Sound effects were originally produced using techniques such as manipulating reel-to-reel tape after recording or through microphone placement during recording. As such, early sound effects were limited to in studio productions. The ability for individual musicians to manipulate instrument sounds in-home became available with the emergence of sound effects modules. Sound effects modules are electronic devices that allow musicians to manipulate the sound produced from an electric or electronic instrument. Earlier stand-alone sound effects modules were impractical as the equipment was both bulky and costly. Thus, the first practical sound effects modules to be used regularly outside of the studio were those built into amplifiers using vacuum tubes. With the emergence of the electronic transistor, sound amplification circuitry was able to be even further condensed into small, portable containers commonly referred to as stompbox units. Stompbox units can be designed to produce one or more effects and typically provide a number of controls for adjusting the extent to which the sound of the instrument is manipulated.
While sound effects modules are used with many different types of musical instruments, sound effects modules are most notably used in conjunction with electric guitars in the form of stompboxes. One issue with the use of stompboxes with electric guitars is cable signal loss, which is due, at least in part, to the length of the guitar cable that is used between the guitar and the stompboxes. The cable signal loss across the guitar cable between where the electronic signal of the guitar is generated to where the sound effect is applied results in a loss in tone, which is undesirable to most musicians. Ideally, tone effects are applied as close to the signal generation as possible in order to reduce the amount of signal loss that occurs before the effect is applied. Another issue associated with stompboxes is their accessibility. Stompboxes are typically either placed at the feet of the user or mounted together on a rack. Thus, in order for a musician to adjust the effects controls they must do so with their feet or be within an arm's reach of the rack. Resultantly, effects controls are typically adjusted before a set or an individual song and are not altered throughout.
Therefore it is an object of the present invention to provide a vacuum tube amplification unit that is integrated into the body of an electric instrument for easy access and manipulation of controls and reduction in signal loss before applied effects. A cartridge receiver is integrated into the body of the instrument, while an amplifier cartridge having an amplification circuit is attached to the instrument via the cartridge receiver. Signal loss between signal generation and the applied sound effect is reduced or altogether eliminated as the cartridge receiver is mounted directly onto the electric instrument, thus reducing the length of wire that the generated electronic signal must traverse in order to reach the amplification circuit. Together, the cartridge receiver and the amplifier cartridge provide electronic connections between the electric instrument and the amplification circuit. The amplification circuit includes a pre-amp assembly and an at least one vacuum tube for amplifying the electronic signal of the electric instrument, as well as a gain control for adjusting the extent to which the amplitude of the electronic signal is increased. The gain control is connected to the amplification cartridge, such that the gain control is within a hand's reach while the electric instrument is being played, thus giving the musician much greater control over the sound of his or her electric instrument. The gain control can be used to overdrive the at least one vacuum tube to generate a distorted sound. Attempts have been made to re-produce the original tube-driven overdrive sound using modern day integrated circuit boards with little success. The present invention allows for the true tube-driven overdrive sound in a footprint that is able to fit directly into an electric instrument.